This invention relates to an electronic fuel-injection control circuit for an internal combustion engine and more particularly to a programmable control circuit designed to improve fuel economy, engine idle and reduce emissions. Reference is made to commonly assigned, co-pending patent application Ser. No. 120,467 filed Feb. 11, 1980, now U.S. Pat. No. 4,305,351, for greater descriptive detail of a fuel injected engine, to which the present invention is illustratively applicable.
In fuel-injection control circuits of the character indicated, and in particular, for such control circuits when used with two-cycle V-6 engines of the type described in co-pending patent application Ser. No. 120,467, all engine cylinders are injected with fuel during each revolution of the engine crankshaft. Fuel injection for all engine cylinders during each crankshaft revolution is necessary at or near a maximum engine throttle opening to provide sufficient fuel for high speed engine operation. However, it has been found that at low speed operation, i.e., at less than maximum engine throttle opening, fuel may be advantageously injected to less than all engine cylinders during each crankshaft revolution with resultant improvement in fuel economy, engine idle and engine emissions.